Mysterious eggs

After all the rain we've had, the woods are dotted with brimful vernal pools, and now that the amphibians have had a chance to court and mate, there are plenty of eggs just beginning to develop. Most of these are so distinctive that I know which species has deposited them right away. The loose, dark ones in clear jelly were put there by female Wood Frogs. The tighter, more compact clusters that can be clear, translucent, or completely opaque came from Spotted Salamanders. And the single eggs laid on the temporary pond bottom by female Spring Peepers, well, those you rarely see at all. Then there are these, which, I knew at a glance, I didn't know. I sent out a distress call to some of the genuine biologists I've worked with over the years, and they were perplexed, too. The best guess, and one that my own research suggested, was that these were from a Jefferson Salamander, a fairly close cousin to the "spotty" and one that's pretty uncommon around here. Since the adults are now long gone, I'm going to have to watch these eggs develop and hatch. The larvae should give me enough identification info to solve this mystery.